V4L/DVB (11663): Fix a warning introduced by git commit ec5f5bf8

/home/v4l/master/v4l/radio-si470x.c: In function 'si470x_fops_release':
/home/v4l/master/v4l/radio-si470x.c:1218: warning: label 'unlock' defined but not used
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/radio/radio-si470x.c

@@ -1214,7 +1214,6 @@ static int si470x_fops_release(struct file *file)
 		usb_autopm_put_interface(radio->intf);
 	}
 
-unlock:
 	mutex_unlock(&radio->disconnect_lock);
 
 done: